CN113597652A

CN113597652A - Method for manufacturing circuit board

Info

Publication number: CN113597652A
Application number: CN202080022411.4A
Authority: CN
Inventors: 大山秀树; 田中孝幸; 松村惠理
Original assignee: Ajinomoto Co Inc
Current assignee: Ajinomoto Co Inc
Priority date: 2019-03-18
Filing date: 2020-03-17
Publication date: 2021-11-02
Also published as: WO2020189692A1; JP7414805B2; EP3944272A4; TW202103188A; JPWO2020189692A1; KR20210138607A; JP2022126796A; JP7420167B2; EP3944272A1

Abstract

The invention provides a method for manufacturing a circuit board, wherein a conductor layer is formed on a magnetic cured product containing magnetic powder by wet plating, wherein generation of magnetic foreign matters can be inhibited even under the condition that the surface of the magnetic cured product layer is not treated by an oxidant. The present invention provides a method for manufacturing a circuit board, which comprises the following steps in order: (1) a step of obtaining a magnetic cured product by thermally curing a resin composition, (2) a step of polishing at least a part of the surface of the magnetic cured product, and (3) a step of forming a conductor layer by wet plating on at least a part of the polished surface of the magnetic cured product, wherein the resin composition comprises: (A) magnetic powder containing nickel, (B) epoxy resin, and (C) curing agent.

Description

Method for manufacturing circuit board

Technical Field

The present invention relates to a method for manufacturing a circuit board using a resin composition containing a magnetic powder; the resin composition.

Background

Many inductors, which are sometimes referred to as power inductors, inductors for high-frequency ranges, and common mode choke coils, are mounted on information terminals such as mobile phones and smartphones. Conventionally, a separate inductor component is mounted on a circuit board, but in recent years, the following methods have been started: a coil is formed by using a conductor pattern of a circuit board, and an inductor is provided inside the circuit board.

For example, patent document 1 discloses a multilayer circuit board with a built-in inductor, in which a spiral conductor pattern is formed in a plurality of layers of the multilayer circuit board, and the ends of the conductor pattern of each layer are connected to an upper layer and a lower layer between layers to form a spiral coil as a whole. Further, patent document 2 discloses a core substrate in which an inductor component is incorporated in a circuit board for the purpose of reducing the thickness of the circuit board.

In the case of manufacturing an inductor component in which an inductor is formed using a plurality of conductor patterns formed on an insulating layer in this manner, it is conceivable to use a resin composition containing a magnetic powder as a material for forming the insulating layer. If an insulating layer (magnetic cured material layer) containing magnetic powder is used, the inductance value can be increased, and leakage of magnetic flux to the outside of the inductor can be prevented. For example, patent document 2 discloses that a magnetic powder is contained in a resin composition constituting a resin composition layer of a resin sheet with a support, and an insulating layer formed is made into a magnetic body.

Further, for example, patent document 3 discloses an inductor component in which a through hole of a circuit board for the inductor component is filled with a resin composition containing a magnetic powder to form a magnetic core, and the magnetic core is disposed in the center of a coil of the circuit board on which a wiring layer is formed, thereby realizing a small size and high inductance.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2009-16504

Patent document 2: japanese laid-open patent publication No. 2012-186440

Patent document 3: japanese patent laid-open publication No. 2016 and 197624.

Disclosure of Invention

Problems to be solved by the invention

In the production of these inductor components (circuit boards), a conductor layer is sometimes formed on a magnetic cured material layer containing magnetic powder, and it is desirable to form the conductor layer by wet plating which is advantageous in terms of cost.

In the case of forming a conductor layer on an insulating layer containing no magnetic powder, a method of forming a conductor layer by treating the surface of an insulating layer with an oxidizing agent is generally used. However, the present inventors have found that: conventionally, when a conductor layer is formed on a magnetic cured layer containing magnetic powder, when the surface of the magnetic cured layer is treated with an oxidizing agent, the resin and the magnetic powder are eluted (eluted), and the magnetic cured layer becomes brittle, so that it is difficult to improve plating adhesion.

Therefore, the present inventors have studied a method of polishing the surface of the magnetic cured layer to form a conductor layer as a process of forming a conductor layer on the magnetic cured layer without using an oxidizing agent. However, the following new problems were found: when the conductor layer is formed on the magnetic cured layer by wet plating after polishing the surface of the magnetic cured layer, magnetic foreign matter, which is considered to be derived from precipitates, and the like of the magnetic powder contained in the magnetic cured layer, is generated in the process of performing wet plating, and the bath, the substrate, and the like are contaminated. In particular, in the case of electroless plating, it was found that contamination is remarkable in a catalyst activation step of activating a catalyst such as palladium on the surface of a magnetic cured product layer by a reducing agent.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a substrate, in which generation of magnetic foreign matter can be suppressed in the manufacture of a circuit substrate in which a conductor layer obtained by wet plating is formed on a magnetic cured material layer containing magnetic powder, without performing treatment of the surface of the magnetic cured material layer with an oxidizing agent.

Means for solving the problems

The present inventors have made extensive studies to achieve the above object, and as a result, have found that: the present inventors have found that the use of a magnetic powder containing nickel as a magnetic powder contained in a resin composition can suppress the generation of magnetic foreign matter in a wet plating process even when the surface of a magnetic cured product layer is not treated with an oxidizing agent, but is instead treated with a polishing treatment, and have completed the present invention.

That is, the present invention includes the following;

[1] a method for manufacturing a circuit board, comprising the following steps in this order: (1) a step of obtaining a magnetic cured product by thermally curing a resin composition, (2) a step of polishing at least a part of the surface of the magnetic cured product, and (3) a step of forming a conductor layer by wet plating on at least a part of the polished surface of the magnetic cured product, wherein the resin composition comprises: (A) magnetic powder containing nickel, (B) epoxy resin, and (C) curing agent;

[2] the method for manufacturing a circuit board according to the above [1], wherein the component (A) is a nickel-iron alloy-based metal powder;

[3] the method for manufacturing a circuit board according to the above item [1] or [2], wherein the nickel content in the component (A) is 30 to 90 mass%;

[4] the method for producing a circuit board according to any one of the above [1] to [3], wherein the content of the component (A) in the resin composition is 70 to 98 mass% assuming that the nonvolatile component in the resin composition is 100 mass%;

[5] the method for producing a circuit board according to any one of the above [1] to [4], wherein the weight retention of the component (A) after immersion in 2N sulfuric acid at 40 ℃ for 5 minutes is 90% or more;

[6] the method for manufacturing a circuit board according to any one of the above [1] to [5], wherein the component (B) contains an epoxy resin which is liquid at 25 ℃;

[7] the method for producing a circuit board according to any one of the above [1] to [6], wherein the component (C) is a curing agent selected from an acid anhydride curing agent, an amine curing agent, and an imidazole curing agent;

[8] the method for producing a circuit board according to any one of the above [1] to [7], wherein the surface of the magnetic cured product obtained in the step (1) has a pencil hardness of F to 5H measured according to JIS K5600-5-4;

[9]according to the above [1]～[8]The method for producing a circuit board according to any one of the above, wherein the magnetic cured product obtained in the step (1) is subjected to a soft etching solution (Na) at 30 ℃₂S₂O₈100g/L，H₂SO₄(75% aqueous solution)) was immersed for 1 minute, and the etching rate (etchenrate) was 25mg/cm²The following;

[10] the method for manufacturing a circuit board according to any one of the above [1] to [9], wherein the resin composition is in a paste form;

[11] a resin composition comprising: (A) magnetic powder containing nickel, (B) epoxy resin, and (C) curing agent.

ADVANTAGEOUS EFFECTS OF INVENTION

By using the magnetic cured product obtained by curing the resin composition of the present invention for the production of a circuit board, the amount of magnetic foreign matter that can be generated in the treatment liquid in the wet plating process can be suppressed even when the surface of the magnetic cured product layer is not treated with an oxidizing agent.

Brief description of the drawings

Fig. 1 is a schematic cross-sectional view of a core substrate as an example of a first embodiment of a method of manufacturing a circuit substrate;

fig. 2 is a schematic cross-sectional view of a core substrate formed with through-holes (vias) as an example of a first embodiment of a method of manufacturing a circuit substrate;

fig. 3 is a schematic cross-sectional view showing a form in which a plated layer is formed in a through-hole as an example of the first embodiment of the method for manufacturing a circuit board;

FIG. 4 is a schematic cross-sectional view showing a form in which through-hole-filling paste is filled in through-holes as an example of the first embodiment of the method for manufacturing a circuit board;

FIG. 5 is a schematic cross-sectional view showing the form of a magnetic cured product obtained by thermally curing a filled through-hole filling paste, which is an example of the first embodiment of the method for producing a circuit board;

FIG. 6 is a schematic cross-sectional view showing a state after polishing a magnetic cured product, which is an example of the first embodiment of the method for manufacturing a circuit board;

FIG. 7 is a schematic cross-sectional view showing a form in which a conductor layer is formed on a polished surface as an example of the first embodiment of the method for manufacturing a circuit board;

fig. 8 is a schematic cross-sectional view showing a form in which a pattern conductor layer is formed, as an example of the first embodiment of the method for manufacturing a circuit board;

fig. 9 is a schematic cross-sectional view for explaining a step (α) as an example of a second embodiment of a method for manufacturing a circuit board;

fig. 10 is a schematic cross-sectional view for explaining a step (α) as an example of a second embodiment of a method for manufacturing a circuit board;

fig. 11 is a schematic cross-sectional view for explaining a step (β) as an example of a second embodiment of a method of manufacturing a circuit board;

fig. 12 is a schematic cross-sectional view showing a form in which a pattern conductor layer is formed, as an example of the second embodiment of the method for manufacturing a circuit board;

fig. 13 is a schematic plan view of an inductor component including a circuit board obtained by the second embodiment of the method for manufacturing a circuit board, as an example, as viewed from one side in the thickness direction thereof;

fig. 14 is a schematic view showing, as an example, a cut end face of a sensor part including a circuit board obtained by the second embodiment of the method for manufacturing a circuit board, cut at a position indicated by a chain line II-II;

fig. 15 is a schematic plan view for explaining a configuration of a first conductor layer in an inductor component including a circuit board obtained by the second embodiment of the method for manufacturing a circuit board, as an example.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are only for the purpose of illustrating the shape, size, and arrangement of the constituent elements in a simplified manner to the extent that the invention can be understood. The present invention is not limited to the following description, and each constituent element may be appropriately modified. In the drawings used in the following description, the same components are denoted by the same reference numerals, and redundant description thereof may be omitted. Further, the configurations described in the embodiments of the present invention are not necessarily limited to being manufactured or used only by the configurations illustrated in the drawings.

[ Circuit Board ]

The circuit board is a board having a conductive layer (circuit) formed on one surface or both surfaces thereof. The circuit board may be used as a wiring board for mounting electronic components such as a semiconductor chip, or may be used as a (multilayer) printed wiring board using the wiring board as an inner layer substrate.

Hereinafter, a method for manufacturing a circuit board will be described.

[ method for manufacturing Circuit Board ]

The method for manufacturing a circuit board of the present invention includes the steps of: (1) a step of obtaining a magnetic cured product by thermally curing the resin composition, (2) a step of polishing at least a part of the surface of the magnetic cured product, and (3) a step of forming a conductor layer on the polished surface of at least a part of the magnetic cured product by wet plating. The resin composition further includes (A) a magnetic powder containing nickel, (B) an epoxy resin, and (C) a curing agent. As described above, in the resin composition of the present invention, since the acid-resistant (a) magnetic powder containing nickel is used as the magnetic powder, by using the magnetic cured product for the production of a circuit board, even when the surface of the magnetic cured product layer is not subjected to a treatment with an oxidizing agent or is subjected to a polishing treatment instead of the treatment, the amount of magnetic foreign matter that can be generated in the treatment liquid in the wet plating process can be suppressed to a low level, and contamination of the bath, the substrate, and the like can be prevented. In particular, a circuit board provided with "a magnetic cured product having a surface containing (a) a magnetic powder containing nickel" and "a conductor layer formed on the surface" can be manufactured while suppressing the amount of magnetic foreign matter generated. In one embodiment, the resin composition of the present invention contains the component (a), whereby a magnetic cured product having hardness suitable for polishing can be easily obtained. Therefore, in this embodiment, the magnetic cured product of the resin composition of the present invention has excellent polishing properties, and thus can be efficiently polished in the (2) polishing step of the wet plating process.

Step (1)

The step (1) is a step of obtaining a magnetic cured product by thermally curing the resin composition. The shape of the magnetic cured product is not particularly limited, and can be appropriately set according to the use mode and the like. The step (1) may include a step of preparing a resin composition. The curing temperature of the resin composition in the step (1) varies depending on the composition and type of the resin composition, but is preferably 120 ℃ or higher, more preferably 130 ℃ or higher, still more preferably 150 ℃ or higher, still more preferably 240 ℃ or lower, still more preferably 220 ℃ or lower, and still more preferably 200 ℃ or lower. The curing time of the resin composition is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 120 minutes or less, further preferably 100 minutes or less, further preferably 90 minutes or less.

Before the resin composition is thermally cured, for the resin composition, a preliminary heat treatment of heating at a temperature lower than the curing temperature may be performed. For example, before the resin composition is thermally cured, the resin composition may be preheated at a temperature of usually 50 ℃ or higher and less than 120 ℃ (preferably 60 ℃ or higher and 110 ℃ or lower, more preferably 70 ℃ or higher and 100 ℃ or lower) for usually 5 minutes or longer (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

The degree of cure of the magnetic cured product obtained in step (1) is preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. The degree of curing can be measured, for example, using a differential scanning calorimeter.

Step (2)

The step (2) is a step of polishing the surface of the cured magnetic material. The surface to be polished may be at least a part of the surface of the cured magnetic material. Examples of the polishing method include buffing polishing and belt polishing. Examples of commercially available polishing and polishing apparatuses include "NT-700 IM" manufactured by Shijing notation.

The arithmetic average roughness (Ra) of the polished surface of the cured magnetic material is preferably 300nm or more, more preferably 350nm or more, and still more preferably 400nm or more, from the viewpoint of improving plating adhesion to the conductor layer. The upper limit is preferably 1000nm or less, more preferably 900nm or less, further preferably 800nm or less. The surface roughness (Ra) can be measured, for example, using a non-contact surface roughness meter.

After the step (2) and before the step (3), a heat treatment step may be performed as necessary for the purpose of further improving the degree of curing of the magnetic cured product. The temperature in the heat treatment step may be set to the above-mentioned curing temperature, and is preferably 120 ℃ or higher, more preferably 130 ℃ or higher, further preferably 150 ℃ or higher, preferably 240 ℃ or lower, further preferably 220 ℃ or lower, further preferably 200 ℃ or lower. The heat treatment time is preferably 5 minutes or more, more preferably 10 minutes or more, further preferably 15 minutes or more, preferably 90 minutes or less, further preferably 70 minutes or less, further preferably 60 minutes or less.

In the step (2), the surface of the cured magnetic material is polished, and the surface is not treated with an oxidizing agent, whereby a conductor layer can be formed on the cured magnetic material, whereby the cured magnetic material can be prevented from becoming brittle, and good plating adhesion can be achieved.

In addition, although a part of the magnetic powder containing nickel (a) may be exposed on the polished surface of the thus-obtained magnetic cured product, the amount of the generated magnetic foreign matter can be suppressed to a low level because the component (a) is acid-resistant (has high resistance to acid).

A process (3)

The step (3) is a step of forming a conductor layer by wet plating on the surface of the magnetic cured product, at least a part of which has been polished. The magnetic powder containing nickel (a) may be present on the polished surface of the magnetic cured product, but the magnetic powder containing nickel (a) is less likely to be eluted into the liquid used for plating, and therefore generation of magnetic foreign matter can be suppressed. Examples of the material of the conductor layer include: single metals such as gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, indium, and the like; an alloy of 2 or more metals selected from gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. Among them, from the viewpoint of versatility, cost, ease of pattern formation, and the like, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nichrome, cupronickel, cupitanium, more preferably chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or nichrome, still more preferably copper is used.

In a preferred embodiment of the step (3), the conductor layer is preferably formed by performing electroless plating as the wet plating treatment, and more preferably, the conductor layer is formed by further performing electrolytic plating after the electroless plating. In this way, in the step (3), the conductor layer is preferably formed by plating on the surface of the magnetic cured product by a semi-additive method, a full-additive method or the like. In the step (3), the conductor layer is preferably formed by a semi-additive method from the viewpoint of ease of manufacturing the conductor layer.

The details of the semi-additive method are first to form a plating seed layer on the surface of the cured magnetic material by electroless plating treatment. Next, a mask pattern is formed on the formed plating seed layer to expose a part of the plating seed layer in accordance with a desired wiring pattern. After a conductor layer is formed on the exposed plating seed layer by electrolytic plating treatment, the mask pattern is removed. Then, the unnecessary plating seed layer is removed by etching or the like, whereby a conductor layer having a desired wiring pattern can be formed.

The electroless plating treatment is performed by immersing the magnetic cured product in an electroless plating solution. Examples of the electroless plating treatment include electroless copper plating, electroless nickel-tungsten plating, electroless tin plating, and electroless gold plating, and electroless copper plating is preferred.

Examples of the electroless plating solution used in the electroless plating treatment include solutions containing copper, nickel, tungsten, tin, gold, palladium, and PdCl₂Etc. of metal ions. In addition, the electroless plating solution may contain other additives such as a reducing agent. Commercially available electroless plating solutions can be used. Examples of commercially available products include "THRU-CUP (スルカップ) PEA" manufactured by Shanmura industries, and "S-KPD" manufactured by KANIGEN, Japan.

The treatment time of the electroless plating treatment is preferably 10 minutes or more, more preferably 20 minutes or more, further preferably 30 minutes or more, preferably 60 minutes or less, more preferably 50 minutes or less, further more preferably 40 minutes or less, from the viewpoint of activating the catalyst.

The treatment temperature of the electroless plating treatment is preferably 10 ℃ or higher, more preferably 20 ℃ or higher, still more preferably 30 ℃ or higher, still more preferably 60 ℃ or lower, still more preferably 55 ℃ or lower, and still more preferably 50 ℃ or lower, from the viewpoint of the efficiency of the formation of the conductor layer.

After a plating seed layer is formed by an electroless plating process, a dry film is laminated on the plating seed layer. Then, exposure and development are performed under predetermined conditions using a photomask so that a part of the plating seed layer is exposed in accordance with a desired wiring pattern, thereby forming a mask pattern. The exposure and development conditions may be performed under known conditions.

As the dry film, a photosensitive dry film formed from a photoresist composition can be used. Examples of such a dry film include a phenolic resin (novolac resin) and an acrylic resin.

The mask pattern is used as a plating mask in an electrolytic copper plating process. After the electrolytic plating treatment, the mask pattern may be removed.

The electrolytic plating treatment is performed by immersing the magnetic cured product after the electroless plating treatment in a plating bath. At this time, a current is passed through the plating bath. Examples of the electrolytic plating treatment include electrolytic copper plating, electrolytic nickel plating, electrolytic tin plating, electrolytic gold plating, etc., and electrolytic copper plating is preferred.

Examples of the plating bath used in the electrolytic plating treatment include baths containing copper sulfate, copper pyrophosphate, copper cyanide, and the like.

The treatment time of the electrolytic plating treatment is preferably 30 minutes or more, more preferably 40 minutes or more, further preferably 50 minutes or more, preferably 90 minutes or less, more preferably 80 minutes or less, further more preferably 70 minutes or less, from the viewpoint of activating the catalyst.

The treatment temperature of the electrolytic plating treatment is preferably 10 ℃ or higher, more preferably 15 ℃ or higher, further preferably 20 ℃ or higher, preferably 50 ℃ or lower, more preferably 40 ℃ or lower, and further more preferably 30 ℃ or lower, from the viewpoint of the efficiency of the formation of the conductor layer.

The current density of the electrolytic plating treatment is preferably 1.0A/dm from the viewpoint of efficiency of formation of the conductor layer²Above, more preferably 1.5A/dm²The above, more preferably 2.0A/dm²Above, it is preferably 4.0A/dm²Hereinafter, more preferably 3.5A/dm²Hereinafter, more preferably 3.0A/dm²The following.

After the conductor layer is formed, annealing treatment may be performed as necessary for the purpose of improving the peel strength of the conductor layer, for example. The annealing treatment can be performed by heating the substrate at 150 to 200 ℃ for 20 to 90 minutes, for example.

From the viewpoint of thinning, the thickness of the conductor layer is preferably 70 μm or less, more preferably 60 μm or less, further more preferably 50 μm or less, further more preferably 40 μm or less, particularly preferably 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less. The lower limit is preferably 1 μm or more, more preferably 3 μm or more, and still more preferably 5 μm or more.

Hereinafter, the first embodiment and the second embodiment will be described as more specific examples of the method of manufacturing the circuit board. Needless to say, the method for manufacturing a circuit board according to the present invention is not limited to the first and second embodiments described below.

< first embodiment >

The circuit board according to the first embodiment includes a substrate having through holes formed therein and a cured magnetic material filling the through holes. Therefore, the method for manufacturing a circuit board according to the first embodiment sequentially includes:

(1A) a step of filling the through hole of the substrate with a resin composition and thermosetting the resin composition to form a magnetic cured product, (2A) a step of polishing at least a part of the surface of the magnetic cured product,

(3A) And forming a conductor layer on the surface of the magnetic cured product, at least a part of which has been polished, by wet plating.

The method for manufacturing a circuit board according to the first embodiment further preferably includes, after the step (2A) and before the step (3A), the steps of:

(2A-1) a conditioning (conditioning) step of treating the surface of the cured magnetic material with a solution containing a surfactant, and (2A-2) a catalyst-forming step of forming a catalyst on the surface of the cured magnetic material;

more preferably, the method further comprises a catalyst activation step (2A-3) of activating the catalyst after the step (2A-2) and before the step (3A). When the steps (2A-1) to (2A-3) are performed after the step (2A) is completed, the generation of insoluble matter and the like generated in the step (2A-2) and the step (2A-3) can be particularly suppressed.

Further, after the step (2A-1) and before the step (2A-2), a microetching step of (2A-1-1) removing the surfactant from a site where the surfactant is not required may be included.

Step (1A) -

The step (1A) is a step of filling the through hole of the substrate with the resin composition and thermally curing the resin composition to form a magnetic cured product. In the step (1A), the magnetic cured product is preferably formed using a magnetic paste. In addition, when the step (1A) is performed, as shown in an example in fig. 1, a step of preparing a core substrate 10 including a support substrate 11, and a first metal layer 12 and a second metal layer 13 formed of a metal such as copper foil provided on both surfaces of the support substrate 11 may be included. Examples of the material of the support substrate 11 include insulating base materials such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate.

As shown in fig. 2, the method may further include a step of forming the through hole 14 in the core substrate 10. The through-holes 14 may be formed by, for example, a drill, laser irradiation, plasma irradiation, or the like. Specifically, the through-hole 14 may be formed by forming a through-hole in the core substrate 10 using a drill or the like.

The formation of through-holes 14 may be performed using commercially available drill bit devices. Examples of a drill device commercially available include "ND-1S 211" manufactured by Hitachi-Viya mechanical Co.

After the core substrate 10 is formed with the through-hole 14, as shown in an example of fig. 3, the method may include: and a step of performing roughening treatment of the core substrate 10 to form plated layers 20 in the through holes 14, on the surface of the first metal layer 12, and on the surface of the second metal layer 13.

As the above-mentioned roughening treatment, any of dry and wet roughening treatments can be performed. Examples of the dry roughening treatment include plasma treatment. In addition, as an example of the wet-type roughening treatment, there is a method of sequentially performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralizing treatment with a neutralizing liquid.

The plating layer 20 can be formed by a plating method, and the step of forming the plating layer 20 by the plating method is the same as the formation of the conductor layer in the step (3A) described later.

After preparing the core substrate 10 in which the plating layers 20 are formed in the through holes 14, the through holes 14 are filled with the resin composition 30a as shown in an example in fig. 4. Examples of the filling method include: a method of filling the resin composition 30a into the through-hole 14 via a squeegee (squeegee), a method of filling the resin composition 30a via a cartridge (cartridge), a method of filling the resin composition 30a by performing mask printing, a roll coating method, an ink jet method, and the like. The resin composition 30a is preferably a magnetic paste.

After filling the through hole 14 with the resin composition 30a, the resin composition 30a is thermally cured, and as shown in an example in fig. 5, the magnetic cured product 30 is formed in the through hole 14. The conditions for thermosetting the resin composition 30a and the degree of curing of the magnetic cured product 30 in the step (1A) are the same as those described in the step (1).

Step (2A) -

The step (2A) is a step of polishing at least a part of the surface of the cured magnetic material. In the step (2A), as in the example shown in fig. 6, the excess magnetic cured material 30 protruding from or adhering to the core substrate 10 is removed by polishing, and planarization is performed. As the polishing method, a method capable of polishing an excess of the magnetic cured product 30 protruding from or adhering to the core substrate 10 can be used. The polishing method is the same as the method described in the step (2).

The arithmetic average roughness (Ra) of the polished surface of the cured magnetic material after the step (2A) is preferably 300nm or more, more preferably 350nm or more, and still more preferably 400nm or more, from the viewpoint of improving the plating adhesion to the conductor layer. The upper limit is preferably 1000nm or less, more preferably 900nm or less, further preferably 800nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

In the step (2A), the surface of the cured magnetic material is polished, and the surface is not treated with an oxidizing agent, whereby a conductor layer can be formed on the cured magnetic material, whereby the cured magnetic material can be prevented from becoming brittle, and good plating adhesion can be achieved.

In addition, on the polished surface of the thus obtained magnetic cured product, part of the magnetic powder (a) containing nickel may be exposed, but since the component (a) is acid-resistant, the amount of the generated magnetic foreign matter can be suppressed to a low level.

After the step (2A) and before the step (3A), a heat treatment step may be performed as necessary for the purpose of further improving the degree of curing of the magnetic cured product, as in the case after the step (2) and before the step (3).

Procedure (2A-1) -

The step (2A-1) is a conditioning step of treating the surface of the magnetic cured product with a solution containing a surfactant. In the step (2A-1), the solution containing a surfactant is usually brought into contact with the surface of the magnetic cured product to adjust the surface charge, so that the surface of the magnetic cured product can be easily cleaned and the catalyst in the step (2A-2) can be adsorbed.

As the solution containing a surfactant used in the step (2A-1), a solution containing a surfactant that can adjust the surface charge so that the adsorption of the catalyst in the step (2A-2) can be performed while the surface of the magnetic cured product is easily washed can be used. Examples of such a solution include an alkali solution containing a surfactant, an acid solution containing a surfactant, and the like, and an alkali solution containing a surfactant is preferable from the viewpoint of suppressing insoluble substances and the like. Examples of the alkali solution include a sodium hydroxide solution and a potassium hydroxide solution.

The pH of the surfactant-containing alkali solution is preferably more than 7, more preferably 8 or more, and further more preferably 10 or more. The upper limit is not particularly limited, and is preferably 14 or less, 13 or less, or the like. The pH of the acid solution containing a surfactant is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more. The upper limit is not particularly limited, and is preferably less than 7, 6 or less.

Examples of the surfactant include cationic surfactants such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts; anionic surfactants such as fatty acid salts such as sodium oleate, alkyl sulfate ester salts, alkylbenzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, sodium alkane sulfonates, and sodium alkyl diphenyl ether sulfonates; nonionic surfactants such as Polyoxyethylene nonylphenyl ether, Polyoxyethylene lauryl ether, Polyoxyethylene styrylphenyl ether, Polyoxyethylene octylphenyl ether, Polyoxyethylene sorbitol tetraoleate, and Polyoxyethylene-polyoxypropylene copolymer.

Commercially available surfactants can be used. Examples of commercially available products include "Securiganh 902" manufactured by Anmedte Japan (ATOTECH JAPAN) and "PED-104" manufactured by Shanmura industries, Inc.

The treatment time in the step (2A-1) is preferably 1 minute or more, more preferably 2 minutes or more, still more preferably 3 minutes or more, still more preferably 20 minutes or less, yet more preferably 15 minutes or less, still more preferably 10 minutes or less, from the viewpoint of facilitating the adsorption of the catalyst.

The temperature of the solution containing the surfactant is preferably 30 ℃ or higher, more preferably 40 ℃ or higher, further preferably 50 ℃ or higher, preferably 90 ℃ or lower, more preferably 80 ℃ or lower, and further more preferably 70 ℃ or lower, from the viewpoint of facilitating the adsorption of the catalyst.

After completion of the step (2A-1), washing treatment with water may be carried out as required.

Step (2A-1-1) -

The step (2A-1-1) is a microetching step for removing the surfactant from a site where the surfactant is not required. In the step (2A-1-1), the surfactant is usually removed from the portions where the surfactant is not needed by bringing the microetching solution into contact with the surface of the magnetic cured product. Examples of the sites where the surfactant is not necessary include the first metal layer 12 and the second metal layer 13.

Examples of the microetching solution include hydrochloric acid, sulfuric acid, hydrogen peroxide water, sodium persulfate, ammonium persulfate, and a liquid formed by a combination thereof.

The concentration of the microetching solution is usually 2N or less, preferably 1.5N or less, more preferably 1N or less, in terms of equivalent concentration (normality), from the viewpoint of removing the surfactant only from the sites where the surfactant is not required, and is preferably 0.1N or more, more preferably 0.2N or more, further more preferably 0.5N or more, from the viewpoint of facilitating the removal of the surfactant.

The temperature of the microetching solution is preferably 10 ℃ or higher, more preferably 15 ℃ or higher, further preferably 20 ℃ or higher, preferably 50 ℃ or lower, more preferably 40 ℃ or lower, further preferably 30 ℃ or lower, from the viewpoint of facilitating the removal of the surfactant.

The treatment time in the step (2A-1-1) is preferably not less than 10 seconds, more preferably not less than 15 seconds, still more preferably not less than 30 seconds, still more preferably not more than 60 seconds, yet more preferably not more than 50 seconds, still more preferably not more than 40 seconds, from the viewpoint of facilitating the removal of the surfactant.

After completion of the step (2A-1-1), washing treatment with water may be carried out as required.

Procedure (2A-2) -

The step (2A-2) is a catalyst formation step of applying a catalyst to the surface of the magnetically hardened material. In the step (2A-2), the adhesion between the magnetic cured product and the conductor layer can be improved by applying a catalyst to the surface of the magnetic cured product. In general, in the step (2A-2), the magnetic cured product is immersed in a solution containing a catalyst, and the catalyst is adsorbed on the surface of the magnetic cured product.

Examples of the catalyst include palladium salts, palladium complex compounds, tin-palladium complex salts, and tin-palladium colloids.

The catalyst-containing solution is usually an alkaline solution. This can significantly suppress the generation of insoluble matter and the like. The pH of the alkaline solution is preferably higher than 7, more preferably 8 or higher, and further more preferably 10 or higher. The upper limit is not particularly limited, and is preferably 14 or less, 13 or less, or the like.

Further, the concentration of the catalyst-containing solution is preferably 1mmol/L or more, more preferably 5mmol/L or more, further preferably 10mmol/L or more, preferably 500mmol/L or less, further preferably 300mmol/L or less, further preferably 100mmol/L or less in terms of equivalent concentration from the viewpoint of adsorbing the catalyst on the whole of the magnetic cured product.

The catalyst-containing solution may be a commercially available solution. Examples of commercially available products include "Activator Neogenth 834" manufactured by Anmedte Japan and "BROWN SURER (ブラウンシューマー)" manufactured by KANIGEN Japan.

The treatment time in the step (2A-2) is preferably 1 minute or more, more preferably 2 minutes or more, still more preferably 3 minutes or more, further preferably 20 minutes or less, further preferably 15 minutes or less, further more preferably 10 minutes or less, from the viewpoint of adsorbing the catalyst to the whole magnetic cured product.

The temperature of the catalyst-containing solution is preferably 10 ℃ or higher, more preferably 20 ℃ or higher, further preferably 30 ℃ or higher, preferably 60 ℃ or lower, further preferably 50 ℃ or lower, further preferably 40 ℃ or lower, from the viewpoint of adsorbing the catalyst to the whole magnetic cured product.

After completion of the step (2A-2), washing treatment with water may be carried out as required.

Procedure (2A-3) -

The step (2A-3) is a catalyst activation step for activating the catalyst. In the step (2A-3), the adhesion between the magnetic cured product and the conductor layer can be improved by activating the catalyst. In general, in the step (2A-3), the magnetic cured product to which the catalyst is applied is immersed in a reducing agent solution to generate nuclei of the catalyst, thereby activating the catalyst applied to the surface of the magnetic cured product.

Conventionally, a general magnetic powder (metal powder not containing Ni or the like) is easily dissolved in a reducing agent solution. In addition, a part or all of the components of the dissolved magnetic powder are precipitated by reduction with the reducing agent, and foreign substances are likely to be generated. However, since the component (a) used in the present invention is hardly dissolved in the reducing agent solution, the generation of foreign substances can be suppressed.

Examples of the reducing agent used in the step (2A-3) include hypophosphites, and a mixed solution of dimethylamine borane and a potassium salt of an organic acid.

The reducing agent solution is usually an acidic solution. Such an acidic solution easily dissolves general magnetic powder, but (a) magnetic powder containing nickel is difficult to dissolve, and therefore generation of insoluble matter and the like can be significantly suppressed. The pH of the acidic solution is preferably 1 or more, more preferably 2 or more, and still more preferably 3 or more. The upper limit is not particularly limited, and is preferably less than 7, 6 or less.

Further, the concentration of the reducing agent in the reducing agent solution is preferably 0.3N or more, more preferably 0.4N or more, further preferably 0.5N or more, preferably 3N or less, further preferably 2N or less, further preferably 1N or less in terms of equivalent concentration, from the viewpoint of activating the catalyst to be provided on the surface of the magnetic cured product.

The reducing agent solution may be a commercially available solution. Examples of commercially available products include "Reducer Accelerator810 mod" manufactured by Anmet Japan "," Reducer Neogenganhwa ", and" K-PVD "manufactured by KANIGEN Japan.

The treatment time in the step (2A-3) is preferably 1 minute or more, more preferably 2 minutes or more, still more preferably 3 minutes or more, preferably 20 minutes or less, still more preferably 15 minutes or less, still more preferably 10 minutes or less, from the viewpoint of activating the catalyst.

The temperature of the reducing agent solution is preferably 10 ℃ or higher, more preferably 20 ℃ or higher, further preferably 30 ℃ or higher, preferably 60 ℃ or lower, further preferably 50 ℃ or lower, further preferably 40 ℃ or lower, from the viewpoint of activating the catalyst.

After completion of the step (2A-3), washing treatment with water may be carried out as required.

A process (3A)

The step (3A) is a step of forming a conductor layer on at least a part of the polished surface of the cured magnetic material by wet plating. In the step (3A), as shown in fig. 7, a conductor layer 40 is formed on the polished cured magnetic material 30 by wet plating. Further, after the conductor layer 40 is formed, as shown in an example in fig. 8, the conductor layer 40, the first metal layer 12, the second metal layer 13, and a part of the plating layer 20 may be removed by a treatment such as etching to form a patterned conductor layer 41. The materials, forming methods, and the like of the conductor layer 40 and the patterned conductor layer 41 in the step (3A) can be applied to the materials, forming methods, and the like shown in the above-described materials, forming methods, and the like of the conductor layer in the step (3).

< second embodiment >

The circuit board in the second embodiment includes: a substrate including a wiring, and a magnetic cured product for sealing and protecting the wiring. For example, the magnetic material is in the form of a magnetic cured product having a layer shape. The method for manufacturing a circuit board according to the second embodiment sequentially includes:

(1B) laminating a magnetic sheet on a substrate so that the resin composition layer is bonded to the substrate, and thermally curing the resin composition layer to form a magnetic cured product,

(2B) A step of polishing at least a part of the surface of the cured magnetic material, and (3B) a step of forming a conductor layer on the polished surface of the cured magnetic material by wet plating.

The method for manufacturing a circuit board according to the second embodiment preferably further includes, after the step (1B) and before the step (2B), (1B-1) a step of drilling the magnetic cured product.

More preferably, the method further comprises, after the step (2B) and before the step (3B):

(2B-1) a conditioning step of treating the surface of the cured magnetic material with a solution containing a surfactant, and (2B-2) a catalyst-forming step of forming a catalyst on the surface of the cured magnetic material;

more preferably, the method further comprises a catalyst activation step of (2B-3) activating the catalyst after the step (2B-2) and before the step (3B).

Further, after the step (2B-1) and before the step (2B-2), the method may further comprise: (2B-1-1) a microetching step of removing the surfactant from a site where the surfactant is not required.

Step (1B)

The step (1B) is: and a step of laminating the magnetic sheet on the substrate so that the resin composition layer is bonded to the substrate, and thermally curing the resin composition layer to form a magnetic cured product. The step (1B) may include a step of preparing a magnetic sheet.

In the step (1B), as shown in an example in fig. 9, the magnetic sheet 310 including the support 330 and the resin composition layer 320a provided on the support 330 is laminated on the inner layer substrate 200 so that the resin composition layer 320a is bonded to the inner layer substrate 200.

The inner layer substrate 200 is an insulating substrate. Examples of the material of the inner layer substrate 200 include insulating base materials such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, and a thermosetting polyphenylene ether substrate. The inner layer substrate 200 may be an inner layer circuit substrate having a wiring or the like embedded in the thickness thereof.

As an example shown in fig. 9, the inner layer substrate 200 includes: first conductor layer 420 provided on first main surface 200a, and external terminal 240 provided on second main surface 200 b. The first conductor layer 420 includes a plurality of wirings. In the illustrated example, only the wiring of the coil-shaped conductive structure 400 constituting the inductor element is shown. The external terminal 240 is a terminal for electrical connection to an external device or the like, not shown. The external terminal 240 may be configured as a part of a conductor layer provided on the second main surface 200 b.

The conductive material that can constitute the first conductive layer 420, the external terminal 240, and the other conductive layers is the same as the conductive layer described in the step (3).

The first conductor layer 420, the external terminal 240, and the other conductor layer may have a single-layer structure, or may have a multilayer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are stacked. The thicknesses of the first conductor layer 420, the external terminal 240, and the other conductor layers are the same as those of the pattern conductor layer in the first embodiment.

The ratio of the line width (L)/the line pitch (S) of the first conductor layer 420 and the external terminal 240 is not particularly limited, but is usually 900/900 μm or less, preferably 700/700 μm or less, more preferably 500/500 μm or less, further preferably 300/300 μm or less, and still further preferably 200/200 μm or less, from the viewpoint of reducing surface irregularities and obtaining a magnetic cured product having excellent smoothness. The lower limit of the line width/pitch ratio is not particularly limited, but is preferably 1/1 μm or more from the viewpoint of making good the filling of the resin composition layer into the space (space) between the wirings.

The inner layer substrate 200 may have a plurality of through holes 220 penetrating the inner layer substrate 200 from the first main surface 200a to the second main surface 200 b. The through-hole inner wiring 220a is provided in the through-hole 220. The through-hole inner wiring 220a electrically connects the first conductor layer 420 and the external terminal 240.

The resin composition layer 320a and the inner layer substrate 200 can be bonded to each other by, for example, heat-crimping the magnetic sheet 310 to the inner layer substrate 200 from the support 330 side. Examples of the member for heat-pressure bonding the magnetic sheet 310 to the inner layer substrate 200 (hereinafter also referred to as "heat-pressure bonding member") include a heated metal plate (stainless steel (SUS) end plate, etc.) and a metal roll (SUS roll). It is preferable that the thermocompression bonding member is not pressed by directly contacting the magnetic sheet 310, but is pressed through a sheet made of an elastic material such as heat-resistant rubber so that the magnetic sheet 310 sufficiently follows the surface irregularities of the inner layer substrate 200.

The temperature at the time of the thermal compression bonding is preferably in the range of 80 to 160 ℃, more preferably 90 to 140 ℃, further more preferably 100 to 120 ℃, the pressure at the time of the thermal compression bonding is preferably in the range of 0.098 to 1.77MPa, more preferably 0.29 to 1.47MPa, and the time at the time of the thermal compression bonding is preferably in the range of 20 to 400 seconds, more preferably 30 to 300 seconds. The magnetic sheet and the inner layer substrate are preferably bonded to each other under a reduced pressure of not more than 26.7 hPa.

The resin composition layer 320a of the magnetic sheet 310 and the inner substrate 200 can be bonded to each other by a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure laminator manufactured by Nikko & company, and a vacuum applicator (vacuum applicator) manufactured by Nikko-Materials.

After the magnetic sheet 310 and the inner layer substrate 200 are joined, the heat and pressure bonding member is pressed under normal pressure (atmospheric pressure), for example, from the support side, whereby the smoothing process of the laminated magnetic sheet 310 can be performed. The pressing conditions for the smoothing treatment may be set to the same conditions as the above-described conditions for the heat and pressure bonding of the laminate. The smoothing treatment can be performed using a commercially available laminator. The lamination and smoothing treatment can be continuously performed using a commercially available vacuum laminator as described above.

After the magnetic sheet is laminated on the inner layer substrate, the resin composition layer is thermally cured to form a magnetic cured product. As shown in fig. 10, the resin composition layer 320a bonded to the inner layer substrate 200 is thermally cured to form the first magnetic cured layer 320. The thermosetting conditions and the degree of curing of the resin composition layer 320a and the first magnetic cured layer 320 are the same as those described in the step (1).

The support 330 may be removed between the step (2B) and the step (1B) after the thermosetting, or may be peeled off after the step (2B).

Alternatively, the step (1B) may be performed by directly applying or printing a paste-like resin composition (magnetic paste) on the inner layer substrate instead of laminating the magnetic sheet on the inner layer substrate.

Procedure (1B-1) -

The step (1B-1) is a step of drilling the magnetic cured product. In the step (1B-1), as shown in fig. 11, a via hole (via hole)360 is formed by drilling the first magnetic cured layer 320. The via hole 360 serves as a path for electrically connecting the first conductor layer 420 and a second conductor layer 440, which will be described later. The formation of the through hole 360 can be performed by the same method as the formation of the through hole described in the step (1).

A process (2B)

The step (2B) is a step of polishing at least a part of the surface of the cured magnetic material. The polishing method in step (2B) may be performed by the same polishing as described in step (2A) of the first embodiment.

The arithmetic average roughness (Ra) of the polished surface of the cured magnetic material after the step (2B) is preferably 300nm or more, more preferably 350nm or more, and still more preferably 400nm or more, from the viewpoint of improving the plating adhesion to the conductor layer. The upper limit is preferably 1000nm or less, more preferably 900nm or less, further preferably 800nm or less. The surface roughness (Ra) can be measured using, for example, a non-contact surface roughness meter.

In the step (2B), the surface of the cured magnetic material is polished, and the surface is not treated with an oxidizing agent, whereby a conductor layer can be formed on the cured magnetic material, whereby the cured magnetic material can be prevented from becoming brittle, and good plating adhesion can be achieved.

In addition, on the polished surface of the thus-obtained magnetic cured product, although the magnetic powder (a) containing nickel may be partially exposed, the amount of magnetic foreign matter produced can be suppressed to a low level because the component (a) is acid-resistant.

The steps (2B-1) to (2B-3) are the steps as described in the steps (2A-1) to (2A-3) of the first embodiment, respectively.

A process (3B)

The step (3B) is a step of forming a conductor layer on at least a part of the polished surface of the cured magnetic material by wet plating. In step (3B), as shown in fig. 12, a second conductor layer 440 is partially formed on the polished surface of the first magnetic cured layer 320. The method for forming the second conductor layer 440 is the same as that described in the first embodiment. In this step, the through-hole wiring 360a is formed in the through-hole 360. The conductor layer 400 is formed by forming the second conductor layer 440. The second conductor layer 440 includes a plurality of wirings.

The second conductor layer 440 may be formed of the same conductor material as the first conductor layer 420. The second conductor layer 440 may have a single-layer structure, or may have a multilayer structure in which 2 or more single metal layers or alloy layers made of different metals or alloys are stacked. When the second conductor layer 440 has a multilayer structure, the layer in contact with the magnetic cured product is preferably a single metal layer of chromium, zinc, or titanium, or an alloy layer of nichrome. In addition, the thickness of the second conductor layer 440 is the same as the thickness of the first conductor layer 420.

The first conductor layer 420 and the second conductor layer 440 may be provided in a spiral shape, for example, as shown in fig. 13 to 15 described later. In one example, the center-side end of the spiral-shaped wiring portion of the second conductor layer 440 is electrically connected to the center-side end of the spiral-shaped wiring portion of the first conductor layer 420 via the through-hole inner wiring 360 a. The other end of the second conductor layer 440 on the outer peripheral side of the spiral wiring portion is electrically connected to the land (land)420a of the first conductor layer 420 via the via-in-via wiring 360 a. Therefore, the other end of the second conductor layer 440 on the outer peripheral side of the spiral wiring portion is electrically connected to the external terminal 240 via the via inner wiring 360a, the pad 420a, and the through-hole inner wiring 220 a.

The coil-shaped conductive structure 400 includes a spiral wiring portion that is a part of the first conductor layer 420, a spiral wiring portion that is a part of the second conductor layer 440, and an in-via wiring 360a that electrically connects the spiral wiring portion of the first conductor layer 420 and the spiral wiring portion of the second conductor layer 440.

After the step (3B), a step of forming a magnetic cured product on the conductor layer may be further performed. In detail, as shown in fig. 14, a second magnetic cured material is formed on the first magnetic cured material layer 320 on which the second conductor layer 440 and the in-via wiring 360a are formed. The second cured magnetic material can be formed by the same steps as those described above.

[ magnetic paste ]

The resin composition of the present invention can be formed into a paste-like magnetic paste by using a liquid epoxy resin or the like, even if it does not contain an organic solvent. When the magnetic paste contains an organic solvent, the content thereof is preferably less than 1.0% by mass, more preferably 0.8% by mass or less, further preferably 0.5% by mass or less, particularly preferably 0.1% by mass or less, based on the total mass of the magnetic paste. The lower limit is not particularly limited, and is 0.001 mass% or more, or not. By reducing the content of the organic solvent in the magnetic paste or not including the organic solvent, generation of voids due to volatilization of the organic solvent can be suppressed, and further, handling property and workability can be improved.

The viscosity of the magnetic paste is preferably 20 pas or more, more preferably 25 pas or more, further preferably 30 pas or more, and 50 pas or more, and is usually less than 200 pas, preferably 180 pas or less, and more preferably 160 pas or less at 25 ℃. The viscosity can be measured by keeping the temperature of the magnetic paste at 25. + -. 2 ℃ using an E-type viscometer.

Such a magnetic paste is useful when filling a through hole of a substrate.

[ magnetic sheet ]

The magnetic sheet comprises a support and a resin composition layer formed of the resin composition of the present invention provided on the support.

From the viewpoint of thinning, the thickness of the resin composition layer is preferably 250 μm or less, more preferably 200 μm or less, still more preferably 150 μm or less and 100 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, and may be usually 5 μm or more.

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferable.

When a film made of a plastic material is used as the support, examples of the plastic material include: polyethylene terephthalate (hereinafter sometimes referred to simply as "PET"), polyester such as polyethylene naphthalate (hereinafter sometimes referred to simply as "PEN"), acrylic polymer such as polycarbonate (hereinafter sometimes referred to simply as "PC") and polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, and the like. Among them, polyethylene terephthalate and polyethylene naphthalate are preferable, and particularly, inexpensive polyethylene terephthalate is preferable.

When a metal foil is used as the support, examples of the metal foil include copper foil and aluminum foil, and copper foil is preferred. As the copper foil, a foil formed of a single metal of copper may be used, and a foil formed of an alloy of copper and another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, or the like) may also be used.

The surface of the support to be bonded to the resin composition layer may be subjected to matting treatment or corona treatment.

Further, as the support, a support with a release layer having a release layer on a surface to be bonded to the resin composition layer can be used. Examples of the release agent used for the release layer of the support having a release layer include 1 or more release agents selected from alkyd resins, polyolefin resins, polyurethane resins, and silicone resins. As the support having a release layer, commercially available products can be used, and examples thereof include: "SK-1", "AL-5", "AL-7" manufactured by Linekuke as a PET film having a release layer containing an alkyd resin-based release agent as a main component; "Lumiror T60" manufactured by Dongli corporation; "Purex" manufactured by Imperial corporation; unipel manufactured by UNITIKA, Inc.

The thickness of the support is not particularly limited, but is preferably in the range of 5 to 75 μm, more preferably 10 to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably within the above range.

The magnetic sheet can be manufactured, for example, by: a magnetic paste obtained by dissolving a resin composition in an organic solvent is prepared, and the magnetic paste is applied to a support by a die coater or the like, and is dried to form a resin composition layer. When the resin composition is in the form of a paste, it can be produced by: the resin composition is directly applied to the support by a die coater or the like to form a resin composition layer.

Examples of the organic solvent include: ketones such as acetone, Methyl Ethyl Ketone (MEK) and cyclohexanone; acetates such as ethyl acetate, butyl acetate, cellosolve acetate (cellosolve acetate), propylene glycol monomethyl ether acetate and carbitol acetate; carbitols such as cellosolve and butyl carbitol; aromatic hydrocarbons such as toluene and xylene; amide solvents such as dimethylformamide, dimethylacetamide (DMAc) and N-methylpyrrolidone. The organic solvent can be used alone in 1 kind, also can be used more than 2 kinds.

The drying can be carried out by a known method such as heating or hot air blowing. The drying conditions are not particularly limited, and the drying is performed under conditions such that the content of the organic solvent in the resin composition layer is 10 mass% or less, preferably 5 mass% or less. The drying conditions also vary depending on the boiling point of the organic solvent in the magnetic paste, and for example, in the case of using a magnetic paste containing 30 to 60 mass% of the organic solvent, the resin composition layer can be formed by drying at 50 to 150 ℃ for 3 to 10 minutes.

In the magnetic sheet, a protective film selected for the support may be laminated on the surface of the resin composition layer that is not bonded to the support (i.e., the surface on the opposite side from the support). The thickness of the protective film is not particularly limited, and is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust or the like to the surface of the resin composition layer and formation of scratches can be suppressed. The magnetic sheet can be rolled for storage. When the magnetic sheet has a protective film, the protective film can be peeled off and used.

[ inductor Components ]

The circuit board of the present invention is preferably an inductor component having an inductor element formed by a patterned conductor layer.

The inductor component includes a circuit board obtained by the method for manufacturing a circuit board of the present invention. In the case where such an inductor component includes the circuit board obtained in the first embodiment of the method for manufacturing a circuit board, the inductor element formed of a conductor is provided at least in part around the magnetic cured product of the resin composition. Such a sensor component can be applied to, for example, the one described in japanese patent laid-open No. 2016-.

Further, in the case of including the circuit board obtained by the second embodiment of the method for manufacturing a circuit board, the inductor component includes a magnetic cured product of the resin composition (resin composition layer) and a conductive structure at least a part of which is embedded in the magnetic cured product, and includes an inductor element composed of the conductive structure and a part of the magnetic cured product extending in the thickness direction of the magnetic cured product and surrounded by the conductive structure. Here, fig. 13 is a schematic plan view of the inductor component incorporating the inductor element as viewed from one side in the thickness direction thereof. Fig. 14 is a schematic view showing a cut end surface of the inductor member cut at a position shown by a chain line II-II shown in fig. 13. Fig. 15 is a schematic top view for explaining the structure of the first conductor layer in the inductor component.

As shown in fig. 13 and 14 as an example, the inductor component 100 is a stacked wiring board having a plurality of magnetic cured material layers (first magnetic cured material layer 320, second magnetic cured material layer 340) and a plurality of conductor layers (first conductor layer 420, second conductor layer 440), that is, a stacked (built-up) magnetic cured material layer and a stacked conductor layer. The inductor component 100 includes an inner layer substrate 200.

According to fig. 14, the first magnetic cured layer 320 and the second magnetic cured layer 340 constitute the magnetic portion 300 of the magnetic cured material that can be regarded as one body. Therefore, the coil-shaped conductive structure 400 is provided so that at least a part thereof is embedded in the magnetic portion 300. That is, in the inductor component 100 of the present embodiment, the inductor element is composed of the coil-shaped conductive structure 400 and the core portion that is a part of the magnetic portion 300 extending in the thickness direction of the magnetic portion 300 and surrounded by the coil-shaped conductive structure 400.

As shown as an example in fig. 15, the first conductor layer 420 includes: a spiral wiring portion for constituting the coil-shaped conductive structure 400, and a rectangular land 420a electrically connected to the through-hole inner wiring 220 a. In the illustrated example, the spiral wiring portion includes: a linear portion, a bent portion bent at a right angle, and a detour portion detouring at the pad 420 a. In the illustrated example, the spiral wiring portion of the first conductor layer 420 has a shape that is generally rectangular in overall outline and is wound in a counterclockwise direction from the center side toward the outer side thereof.

Similarly, a second conductor layer 440 is disposed on the first magnetic cured layer 320. The second conductor layer 440 includes a spiral wiring portion for constituting the coil-shaped conductive structure 400. In fig. 13 or 14, the spiral wiring portion includes a linear portion and a bent portion bent at a right angle. In fig. 13 or 14, the spiral wiring portion of the second conductor layer 440 has a shape that is generally rectangular in overall outline and is wound in a clockwise direction from the center side toward the outer side thereof.

Such an inductor component can be used as a wiring board for mounting electronic components such as semiconductor chips, and can also be used as a (multilayer) printed wiring board using the wiring board as an inner layer substrate. The chip inductor component can be used as a chip inductor component obtained by singulating the wiring board, or as a printed wiring board having the chip inductor component mounted on the surface thereof.

In addition, semiconductor devices of various forms can be manufactured using the wiring board. The semiconductor device including the wiring board can be suitably used for electric products (e.g., computers, mobile phones, digital cameras, televisions, and the like), vehicles (e.g., motorcycles, automobiles, electric trains, ships, aircrafts, and the like), and the like.

[ resin composition ]

The resin composition of the present invention comprises (a) a magnetic powder containing nickel, (B) an epoxy resin, and (C) a curing agent. The resin composition may further contain (D) a nonmagnetic inorganic filler, and further may contain (E) other additives as required.

By using the magnetic cured product of the resin composition for the production of a circuit board, even when the surface of the magnetic cured product is not treated or is subjected to polishing treatment instead of the treatment, the amount of magnetic foreign matter that can be generated in the treatment liquid in the wet plating process can be suppressed, and contamination of the bath, the substrate, and the like can be prevented. In one embodiment, the resin composition of the present invention contains the component (a), and thus a magnetic cured product having hardness suitable for polishing can be easily obtained. Therefore, in this embodiment, the resin composition of the present invention is excellent in the polishing property of the magnetic cured product. The components of the resin composition of the present invention are explained below.

(A) magnetic powder containing nickel

The resin composition of the present invention contains (a) a magnetic powder containing nickel. Examples of the magnetic powder containing nickel include pure nickel powder; iron oxide powders containing nickel such as Ni-Zn ferrite powders, Ba-Ni ferrite powders, and Ba-Ni-Co ferrite powders; and nickel-iron alloy-based metal powders such as Fe-Ni-Cr alloy powders, Fe-Ni-Mo alloy powders, and Fe-Ni-Mo-Cu alloy powders.

Among the magnetic powder containing nickel, at least one selected from iron oxide powder containing nickel and nickel-iron alloy-based metal powder is preferable, and nickel-iron alloy-based metal powder is more preferable, and Fe — Ni-based alloy powder and Fe — Ni — Mo-based alloy powder are particularly preferable. The iron oxide powder containing nickel may contain at least one selected from Cu, Mn, and Zn in addition to Fe and Ni. The nickel-iron alloy-based metal powder may contain, in addition to Fe and Ni, an iron alloy-based metal powder containing at least one selected from Si, Cr, Al, Mo, Cu, and Co.

The content of nickel in the component (a) is, for example, 10 mass% or more, 20 mass% or more, 30 mass% or more, preferably 35 mass% or more, more preferably 40 mass% or more, particularly preferably 45 mass% or more, from the viewpoint of remarkably obtaining the desired effect of the present invention. The upper limit is not particularly limited, and may be, for example, 100 mass% or less, less than 100 mass%, 95 mass% or less, 90 mass% or less, 85 mass% or less, or the like.

(A) The iron content in the component (b) is not particularly limited, but is, for example, 90 mass% or less, 80 mass% or less, 70 mass% or less, preferably 65 mass% or less, more preferably 60 mass% or less, particularly preferably 55 mass% or less. The lower limit is not particularly limited, and may be, for example, 0 mass% or more, more than 0 mass%, 5 mass% or more, 10 mass% or more, 15 mass% or more, or the like.

As the component (A), commercially available magnetic powder can be used. Specific examples of commercially available magnetic powders that can be used include "MA-RCO-5" manufactured by DOWAECONTRONICS, and "80% Ni-4 Mo" manufactured by Epson Atmix. The magnetic powder may be used alone or in combination of two or more.

(A) The component is preferably spherical. The value (aspect ratio) obtained by dividing the length of the major axis of the magnetic powder by the length of the minor axis is preferably 2 or less, more preferably 1.5 or less, and still more preferably 1.2 or less. Generally, when the magnetic powder has a non-spherical flat shape, the relative permeability is more easily improved. However, in particular, when spherical magnetic powder is used, it is generally preferable from this viewpoint to obtain a paste having a preferable viscosity while reducing magnetic loss.

From the viewpoint of improving the relative permeability, the average particle diameter of the component (A) is preferably 0.01 μm or more, more preferably 0.5 μm or more, and still more preferably 1 μm or more. The average particle diameter of the component (A) is preferably 30 μm or less, more preferably 20 μm or less, still more preferably 10 μm or less.

(A) The average particle diameter of the component can be measured by a laser diffraction scattering method based on Mie scattering theory. Specifically, the particle size distribution of the magnetic powder can be prepared on a volume basis by a laser diffraction scattering particle size distribution measuring apparatus, and the median particle size is measured as an average particle size. As the measurement sample, a sample obtained by dispersing magnetic powder in water by ultrasonic waves can be preferably used. As the laser diffraction scattering type particle size distribution measuring device, there can be used "LA-500" manufactured by horiba, Ltd., SALD-2200 "manufactured by Shimadzu, Ltd.

From the viewpoint of improving the relative permeability, the specific surface area of the component (A) is preferably 0.05m²More than g, preferably 0.1m²More preferably 0.3m or more in terms of a molar ratio of the compound to the metal²More than g. Further, the specific surface area of the component (A) is preferably 10m²A ratio of less than g, more preferably 8m²A total of 5m or less²The ratio of the carbon atoms to the carbon atoms is less than g. The specific surface area of the magnetic powder can be measured by the BET method.

From the viewpoint of remarkably obtaining the desired effect of the present invention, the undissolved ratio of the component (a) in acid immersion, that is, the weight retention ratio, is preferably 70% or more, more preferably 80% or more, further preferably 90% or more, particularly preferably 95% or more, when immersed in 2N sulfuric acid at 40 ℃ for 5 minutes, for example.

The content (vol%) of the component (a) is preferably 10 vol% or more, more preferably 20 vol% or more, and still more preferably 30 vol% or more, when the nonvolatile component in the resin composition is 100 vol%, from the viewpoints of increasing the relative permeability and reducing the loss factor. The content (% by volume) of the component (a) is preferably 85% by volume or less, more preferably 80% by volume or less, and still more preferably 75% by volume or less.

The content (mass%) of the component (a) is preferably 70 mass% or more, more preferably 75 mass% or more, and still more preferably 78 mass% or more, when the nonvolatile component in the resin composition is 100 mass%, from the viewpoints of improving the relative permeability and reducing the loss factor. The content (% by mass) of the component (a) is preferably 98% by mass or less, more preferably 95% by mass or less, and still more preferably 90% by mass or less.

(B) epoxy resin

The resin composition of the present invention contains (B) an epoxy resin.

Examples of the epoxy resin (B) include a biscresol (bixylenol) type epoxy resin, a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a bisphenol AF type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol novolac (naphthol novolac) type epoxy resin, a phenol novolac (phenol novolac) type epoxy resin, a tert-butyl-catechol type epoxy resin, a naphthalene type epoxy resin, a naphthol type epoxy resin, an anthracene type epoxy resin, a glycidylamine type epoxy resin, a glycidyl ester type epoxy resin, a cresol novolac (cresol novolac) type epoxy resin, a biphenyl type epoxy resin, a linear aliphatic epoxy resin, an epoxy resin having a butadiene structure, an alicyclic epoxy resin, a heterocyclic type epoxy resin, a spiro ring-containing epoxy resin, a cyclohexane type epoxy resin, a bisphenol a epoxy resin, a dicyclopentadiene type epoxy resin, a phenol type epoxy resin, an anthracene type epoxy resin, a naphthol type epoxy resin, a bisphenol a, Cyclohexane dimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, etc. The epoxy resin may be used alone or in combination of two or more.

In the resin composition, it is preferable that the epoxy resin (B) contains an epoxy resin having 2 or more epoxy groups in 1 molecule. From the viewpoint of remarkably obtaining the desired effect of the present invention, the proportion of the epoxy resin having 2 or more epoxy groups in 1 molecule is preferably 50% by mass or more, more preferably 60% by mass or more, particularly preferably 70% by mass or more, relative to 100% by mass of the nonvolatile component of the epoxy resin (B).

The epoxy resin includes an epoxy resin that is liquid at a temperature of 25 ℃ (hereinafter sometimes referred to as "liquid epoxy resin") and an epoxy resin that is solid at a temperature of 25 ℃ (hereinafter sometimes referred to as "solid epoxy resin"). In one embodiment, the resin composition of the present invention contains a liquid epoxy resin as the epoxy resin. In one embodiment, the resin composition of the present invention contains a solid epoxy resin as the epoxy resin. In the resin composition of the present invention, the epoxy resin may be contained only as a liquid epoxy resin, or may be contained only as a solid epoxy resin, or may be contained in combination with a liquid epoxy resin, but in a preferred embodiment, only a liquid epoxy resin is contained.

The liquid epoxy resin is preferably a liquid epoxy resin having 2 or more epoxy groups in 1 molecule.

The liquid epoxy resin is preferably a bisphenol a type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AF type epoxy resin, a naphthalene type epoxy resin, a glycidyl ester type epoxy resin, a glycidyl amine type epoxy resin, a phenol novolac type epoxy resin, an alicyclic epoxy resin having an ester skeleton, a cyclohexane type epoxy resin, a cyclohexane dimethanol type epoxy resin, a glycidyl amine type epoxy resin, or an epoxy resin having a butadiene structure.

Specific examples of the liquid epoxy resin include: "HP 4032", "HP 4032D" and "HP 4032 SS" (naphthalene epoxy resins) manufactured by DIC; "828 US", "828 EL", "jER 828 EL", "825", "EPIKOTE 828 EL" (bisphenol A type epoxy resin) manufactured by Mitsubishi chemical company; "jER 807" and "1750" (bisphenol F type epoxy resin) manufactured by Mitsubishi chemical corporation; "jER 152" (phenol novolac type epoxy resin) manufactured by mitsubishi chemical corporation; "630" and "630 LSD" (glycidyl amine type epoxy resins) manufactured by mitsubishi chemical corporation; "ZX 1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nissian Ciki Kaisha; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX; "CELLOXIDE 2021P" (alicyclic epoxy resin having an ester skeleton) manufactured by Dailuo corporation; "PB-3600" manufactured by Daxylonite, JP-100 "and JP-200" manufactured by Nippon Caoda (a butadiene-structured epoxy resin); "ZX 1658" and "ZX 1658 GS" (liquid 1, 4-glycidylcyclohexane-type epoxy resins) manufactured by Nippon iron and Japan chemical Co., Ltd. These may be used alone or in combination of two or more.

The solid epoxy resin is preferably a solid epoxy resin having 3 or more epoxy groups in 1 molecule, and more preferably an aromatic solid epoxy resin having 3 or more epoxy groups in 1 molecule.

The solid epoxy resin is preferably a biphenol-type epoxy resin, a naphthalene-type tetrafunctional epoxy resin, a cresol novolak-type epoxy resin, a dicyclopentadiene-type epoxy resin, a trisphenol-type epoxy resin, a naphthol-type epoxy resin, a biphenyl-type epoxy resin, a naphthylene ether-type epoxy resin, an anthracene-type epoxy resin, a bisphenol a-type epoxy resin, a bisphenol AF-type epoxy resin, or a tetraphenylethane-type epoxy resin.

Specific examples of the solid epoxy resin include: HP4032H (naphthalene epoxy resin) manufactured by DIC; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resins) manufactured by DIC; "N-690" (cresol novolac type epoxy resin) manufactured by DIC; "N-695" (cresol novolac type epoxy resin) manufactured by DIC; "HP-7200" (dicyclopentadiene type epoxy resin) manufactured by DIC; "HP-7200 HH", "HP-7200H", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S" and "HP 6000" (naphthylene ether type epoxy resins) manufactured by DIC; EPPN-502H (trisphenol type epoxy resin) manufactured by Nippon chemical Co., Ltd.; "NC 7000L" (naphthol novolac type epoxy resin) manufactured by japan chemicals); "NC 3000H", "NC 3000L" and "NC 3100" (biphenyl type epoxy resin) manufactured by japan chemical company; ESN475V (naphthol type epoxy resin) manufactured by Nippon iron and gold Chemicals; ESN485 (naphthol novolac type epoxy resin) manufactured by Nippon iron and gold Chemicals, Ltd; "YX 4000H", "YX 4000", "YL 6121" (biphenyl type epoxy resin) manufactured by Mitsubishi chemical company; "YX 4000 HK" (bisphenol type epoxy resin) manufactured by Mitsubishi chemical corporation; YX8800 (anthracene-based epoxy resin) available from Mitsubishi chemical corporation; "YX 7700" (novolac epoxy resin containing a xylene structure) manufactured by mitsubishi chemical corporation; PG-100 and CG-500 manufactured by Osaka gas chemical company; "YL 7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi chemical corporation; "YL 7800" (fluorene-based epoxy resin) manufactured by Mitsubishi chemical corporation; "jER 1010" (solid bisphenol a type epoxy resin) manufactured by mitsubishi chemical corporation; "jER 1031S" (tetraphenylethane-type epoxy resin) manufactured by Mitsubishi chemical corporation, and the like. These may be used alone or in combination of two or more.

When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin (B), the mass ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin/solid epoxy resin) is preferably 1 or more, more preferably 10 or more, particularly preferably 50 or more, in terms of mass ratio.

(B) The epoxy equivalent of the epoxy resin is preferably 50g/eq to 5000g/eq, more preferably 50g/eq to 3000g/eq, still more preferably 80g/eq to 2000g/eq, and still more preferably 110g/eq to 1000g/eq. By setting the range, the crosslinking density of the magnetic cured product of the magnetic sheet becomes sufficient, and a magnetic cured product layer having a small surface roughness can be provided. The epoxy equivalent is the mass of the resin containing 1 equivalent of epoxy group. The epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin (B) is preferably 100 to 5000, more preferably 250 to 3000, and still more preferably 400 to 1500, from the viewpoint of remarkably obtaining the desired effect of the present invention. The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by a Gel Permeation Chromatography (GPC) method.

(B) The content of the epoxy resin is not particularly limited, and the content of the (B) epoxy resin is preferably 1 mass% or more, more preferably 5 mass% or more, further preferably 8 mass% or more, particularly preferably 10 mass% or more, when the nonvolatile content in the resin composition is 100 mass%, from the viewpoint of remarkably obtaining the desired effect of the present invention. From the viewpoint of remarkably obtaining the desired effect of the present invention, the upper limit thereof is preferably 50% by mass or less, more preferably 40% by mass or less, further more preferably 30% by mass or less, particularly preferably 20% by mass or less.

(C) curing agent

The resin composition of the present invention comprises (C) a curing agent.

The curing agent (C) is not particularly limited as long as it has a function of curing an epoxy resin, and examples thereof include phenol-based curing agents, naphthol-based curing agents, acid anhydride-based curing agents, active ester-based curing agents, benzoxazine-based curing agents, cyanate-based curing agents, carbodiimide-based curing agents, phosphorus-based curing agents, amine-based curing agents, imidazole-based curing agents, guanidine-based curing agents, and metal-based curing agents. Among them, acid anhydride-based curing agents, amine-based curing agents, and imidazole-based curing agents are preferred. (C) One curing agent may be used alone, or two or more curing agents may be used in combination.

As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a phenolic structure (novolak structure) or a naphthol-based curing agent having a phenolic structure is preferable from the viewpoint of heat resistance and water resistance. From the viewpoint of adhesion to an adherend, a nitrogen-containing phenol-based curing agent or a nitrogen-containing naphthol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent or a triazine skeleton-containing naphthol-based curing agent is more preferable. Among them, phenol novolak resin (phenol novolak resin) having a triazine skeleton is preferable from the viewpoint of satisfying heat resistance, water resistance, and adhesion to a high degree. Specific examples of the phenol-based curing agent and the naphthol-based curing agent include "MEH-7700", "MEH-7810", "MEH-7851", "MEH-8000H", "NHN", "CBN", "GPH", manufactured by Nippon chemical company, "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN-495", "SN-375", "SN-395", and "LA-7052", "LA-7054", "LA-3018-50P", "LA-1356", and "TD 2090", manufactured by DIC company.

Examples of the acid anhydride-based curing agent include those having 1 or more acid anhydride groups in one molecule. Specific examples of the acid anhydride-based curing agent include: phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5- (2, 5-dioxotetrahydro-3-furanyl) -3-methyl-3-cyclohexene-1, 2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4' -diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9 b-hexahydro-5- (tetrahydro-2, 5-dioxo-3-furanyl) -naphtho [1,2-C furan-1, 3-dione, ethylene glycol bis (trimellitic anhydride ester), methyl bicyclo [2.2.1] heptane-2, 3-dicarboxylic anhydride/bicyclo [2.2.1] heptane-2, 3-dicarboxylic anhydride (commercially available product, HNA-100 manufactured by Nippon chemical and chemical Co., Ltd.), styrene-maleic acid resin obtained by copolymerizing styrene and maleic acid, and other polymer-type acid anhydrides.

The active ester-based curing agent is not particularly limited, and in general, a compound having 2 or more ester groups having high reactivity in one molecule, such as phenol esters, thiophenol esters, N-hydroxylamine esters, and esters of heterocyclic hydroxy compounds, is preferably used. The active ester-based curing agent is preferably a compound obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxyl compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester-based curing agent obtained from a carboxylic acid compound and a hydroxyl compound is preferable, and an active ester-based curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol a, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol a, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α -naphthol, β -naphthol, 1, 5-dihydroxynaphthalene, 1, 6-dihydroxynaphthalene, 2, 6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolac (phenol novolak) and the like. Here, the "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing 2 molecules of phenol with 1 molecule of dicyclopentadiene.

Specifically, an active ester compound having a dicyclopentadiene type diphenol structure, an active ester compound having a naphthalene structure, an active ester compound having an acetyl compound of a phenol novolac resin, and an active ester compound having a benzoyl compound of a phenol novolac resin are preferable, and among them, an active ester compound having a naphthalene structure and an active ester compound having a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene-type diphenol structure" means a divalent structural unit formed from phenylene-dicyclopentylene (ジシクロペンタレン) -phenylene.

As commercially available products of the active ester-based curing agent, examples of the active ester compound having a dicyclopentadiene type diphenol structure include "EXB 9451", "EXB 9460S", "HPC-8000H", "HPC-8000-65T", "HPC-8000H-65 TM", "EXB-8000L-65 TM" (manufactured by DIC); examples of the active ester compound having a naphthalene structure include "EXB 9416-70 BK" and "EXB 8150-65T" (manufactured by DIC); examples of the active ester compound containing an acetylated novolak resin include "DC 808" (manufactured by Mitsubishi chemical corporation); examples of the active ester compound containing a benzoyl compound of a novolak resin include "YLH 1026" (manufactured by Mitsubishi chemical corporation); examples of the active ester-based curing agent for the acetylated novolak resin include "DC 808" (manufactured by mitsubishi chemical corporation); examples of the active ester-based curing agent for the benzoylate of the novolak resin include "YLH 1026" (manufactured by Mitsubishi chemical corporation), "YLH 1030" (manufactured by Mitsubishi chemical corporation), and "YLH 1048" (manufactured by Mitsubishi chemical corporation); and the like.

Specific examples of the benzoxazine-based curing agent include "JBZ-OP 100D" and "ODA-BOZ" manufactured by JFE chemical company; HFB2006M manufactured by Showa Polymer Co., Ltd, "P-d", "F-a" manufactured by four national chemical industries, Ltd.

Examples of the cyanate ester curing agent include bisphenol A dicyanate, polyphenol cyanate (oligo (3-methylene-1, 5-phenylene cyanate)), 4 '-methylenebis (2, 6-dimethylphenylcyanate), 4' -ethylenediphenyldicyanate, hexafluorobisphenol A dicyanate, 2-bis (4-cyanate) phenylpropane, difunctional cyanate ester resins such as 1, 1-bis (4-cyanate-ylphenylmethane), bis (4-cyanate-3, 5-dimethylphenyl) methane, 1, 3-bis (4-cyanate-ylphenyl-1- (methylethylidene)) benzene, bis (4-cyanate-ylphenyl) sulfide, and bis (4-cyanate-ylphenyl) ether; polyfunctional cyanate ester resins derived from phenol novolac resins, cresol novolac resins, and the like; prepolymers obtained by triazinating a part of these cyanate ester resins, and the like. Specific examples of the cyanate ester-based curing agent include "PT 30" and "PT 60" (both phenol novolac-type polyfunctional cyanate ester resins), "BA 230" and "BA 230S 75" (prepolymers in which a part or all of bisphenol a dicyanate is triazinized to form a trimer), which are manufactured by Lonza Japan.

Specific examples of the carbodiimide-based curing agent include "V-03" and "V-07" manufactured by Nisshinbo chemical Co.

Examples of the phosphorus-based curing agent include triphenylphosphine, a phosphonium borate compound, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl) triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.

Examples of the amine-based curing agent include aliphatic amine-based curing agents such as triethylamine, tributylamine, 4-Dimethylaminopyridine (DMAP), benzyldimethylamine, 2,4, 6-tris (dimethylaminomethyl) phenol, 1, 8-diazabicyclo [5.4.0] undecene, and 4-dimethylaminopyridine and 1, 8-diazabicyclo [5.4.0] undecene; benzidine, o-tolidine, 4 '-diaminodiphenylmethane, 4' -diamino-3, 3 '-dimethyldiphenylmethane ("KAYABOND C-100" manufactured by Nippon Kagaku Co., Ltd., a commercial product), 4' -diamino-3, 3 '-diethyldiphenylmethane ("KAYAHARD A-A" manufactured by Nippon Kagaku Co., Ltd., a commercial product), 4' -diamino-3, 3',5,5' -tetramethyldiphenylmethane ("KAYABOND C-200S" manufactured by Nippon Kagaku Co., Ltd., a commercial product), 4 '-diamino-3, 3',5,5 '-tetraethyldiphenylmethane ("KAYABOND C-300S" manufactured by Nippon Kagaku Co., a commercial product), 4' -diamino-3, 3' -diethyl-5, 5' -dimethyldiphenylmethane, 4' -diaminodiphenyl ether, 1, 3-bis (3-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) benzene, 1, 4-bis (3-aminophenoxy) benzene, 1, 4-bis (4-aminophenoxy) benzene, 1, 3-bis (4-aminophenoxy) neopentane, 4' - [1, 3-phenylenebis (1-methylethylidene) ] diphenylamine (M) manufactured by the triple-well chemical industry, as a commercial product), 4' - [1, 4-phenylenebis (1-methylethylidene) ] diphenylamine (diphenylamine P) manufactured by the triple-well chemical industry, as a commercial product), 2, aromatic amine-based curing agents such as 2-bis [4- (4-aminophenoxy) phenyl ] propane (commercially available as "BAPP" from Hill refining, and Monochamus domestica), 2-bis [4- (4-aminophenoxy) phenyl ] hexafluoropropane, and 4,4' -bis (4-aminophenoxy) biphenyl.

Examples of the imidazole-based curing agent include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1, 2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-heptadecylimidazole, 2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-methylimidazole, 2-heptadecylimidazole, 2-ethylimidazole, 2-methylimidazole, 2-ethylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-methylimidazole, and 2-bromoimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2, 4-diamino-6- [2' -methylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -undecylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -ethyl-4 ' -methylimidazolyl- (1') ] -ethyl-s-triazine, 2, 4-diamino-6- [2' -methylimidazolyl- (1') ] -ethyl-s-triazine An imidazole compound such as an ethyl-s-triazine isocyanuric acid adduct, a 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4, 5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2, 3-dihydro-1H-pyrrolo [1,2-a ] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, or an adduct of an imidazole compound with an epoxy resin.

As the imidazole-based curing agent, commercially available products can be used, and examples thereof include "P200-H50" manufactured by Mitsubishi chemical corporation.

Examples of the guanidine-based curing agent include: dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1- (o-tolyl) guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5, 7-triazabicyclo [4.4.0] dec-5-ene, 7-methyl-1, 5, 7-triazabicyclo [4.4.0] dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecyl biguanide, 1-dimethylbiguanide, 1-diethylbiguanide, 1-cyclohexylbiguanide, 1-allylbiguanide, 1-phenylbiguanide, 1- (o-tolyl) biguanide and the like.

Examples of the metal-based curing agent include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of the organometallic complex include: organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, organic zinc complexes such as zinc (II) acetylacetonate, organic iron complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

The amount ratio of the epoxy resin to the curing agent is preferably in the range of 1:0.2 to 1:2, more preferably 1:0.3 to 1:1.5, further preferably 1:0.4 to 1:1.2 in terms of the ratio of [ total number of epoxy groups of epoxy resin ]: to [ total number of reactive groups of curing agent ]. The reactive group of the curing agent is an active hydroxyl group, an active ester group, or the like, and varies depending on the kind of the curing agent. The total number of epoxy groups of the epoxy resin is a value obtained by summing the values obtained by dividing the mass of the nonvolatile components of the respective epoxy resins by the epoxy equivalent weight for all the epoxy resins, and the total number of reactive groups of the curing agent is a value obtained by summing the values obtained by dividing the mass of the nonvolatile components of the respective curing agents by the equivalent weight of the reactive groups for all the curing agents. When the amount ratio of the epoxy resin to the curing agent is within the above range, the heat resistance of the resulting cured product is further improved.

(C) The content of the curing agent is not particularly limited, and is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 0.5% by mass or more, assuming that the nonvolatile content in the resin composition is 100% by mass. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and still more preferably 2% by mass or less.

Non-magnetic inorganic filling material

The resin composition of the present invention may contain (D) a nonmagnetic inorganic filler as an optional component. (D) The non-magnetic inorganic filler is a component having no magnetism, unlike the component (A).

(D) The material of the nonmagnetic inorganic filler is not particularly limited, and examples thereof include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate zirconate, barium zirconate, calcium zirconate, zirconium phosphate tungstate, etc., and silica is particularly preferable. Examples of the silica include amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica and the like. Further, as the silica, spherical silica is preferable. (D) The nonmagnetic inorganic filler may be used alone or in combination of two or more.

Examples of commercially available products of the nonmagnetic inorganic filler (D) include "RY-200" and "A200" manufactured by AEROSIL, Japan; UFP-30 manufactured by electrochemical chemical industry; "SP 60-05" and "SP 507-05" manufactured by Nissi iron-alloy materials Corp; "YC 100C", "YA 050C", "YA 050C-MJE", "YA 010C" manufactured by Admatech (Admatech); UFP-30 manufactured by DENKA corporation; "Silfil (シルフィル) NSS-3N", "Silfil NSS-4N", "Silfil NSS-5N" manufactured by Deshan (Tokuyama); "SC 2500 SQ", "SO-C4", "SO-C2" and "SO-C1" manufactured by Yadama corporation; and the like.

(D) The average particle size of the nonmagnetic inorganic filler is not particularly limited, but is preferably 20 μm or less, more preferably 10 μm or less, further preferably 8 μm or less, further preferably 6 μm or less, particularly preferably 5 μm or less, from the viewpoint of obtaining the desired effect of the present invention. From the viewpoint of obtaining the desired effect of the present invention, the lower limit of the average particle size of the nonmagnetic inorganic filler is preferably 0.1 μm or more, more preferably 1 μm or more, further preferably 2 μm or more, further preferably 3 μm or more, particularly preferably 4 μm or more. The average particle diameter of the nonmagnetic inorganic filler can be measured by a laser diffraction-scattering method based on Mie scattering theory. Specifically, the particle size distribution of the nonmagnetic inorganic filler can be measured on a volume basis by a laser diffraction scattering particle size distribution measuring apparatus, and the median particle size is measured as an average particle size. As the measurement sample, a sample obtained by weighing 100mg of the nonmagnetic inorganic filler and 10g of methyl ethyl ketone in a vial and dispersing them by ultrasonic waves for 10 minutes can be used. For the measurement sample, the volume-based particle size distribution of the nonmagnetic inorganic filler was measured by a flow cell method using a laser diffraction type particle size distribution measuring apparatus with the wavelengths of the light source used being blue and red, and the average particle size was calculated from the obtained particle size distribution as the median particle size. Examples of the laser diffraction type particle size distribution measuring apparatus include "LA-960" manufactured by horiba, Ltd.

From the viewpoint of improving moisture resistance and dispersibility, the non-magnetic inorganic filler (D) is preferably treated with at least one surface treatment agent selected from the group consisting of an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, an alkoxysilane compound, an organosilazane compound, and a titanate coupling agent. Examples of commercially available surface-treating agents include "KBM 403" (3-glycidoxypropyltrimethoxysilane) available from shin-Etsu chemical Co., Ltd., "KBM 803" (3-mercaptopropyltrimethoxysilane) available from shin-Etsu chemical Co., Ltd., "KBE 903" (3-aminopropyltriethoxysilane) available from shin-Etsu chemical Co., Ltd., "KBM 573" (N-phenyl-3-aminopropyltrimethoxysilane) available from shin-Etsu chemical Co., Ltd., "SZ-31" (hexamethyldisilazane) manufactured by shin-Etsu chemical industries, "KBM 103" (phenyltrimethoxysilane) manufactured by shin-Etsu chemical industries, "KBM-4803" (long-chain epoxy silane coupling agent) manufactured by shin-Etsu chemical industries, and "KBM-7103" (3,3, 3-trifluoropropyltrimethoxysilane) manufactured by shin-Etsu chemical industries.

From the viewpoint of improving the dispersibility of the nonmagnetic inorganic filler, the degree of the surface treatment with the surface treatment agent is preferably within a predetermined range. Specifically, 100% by mass of the nonmagnetic inorganic filler is preferably surface-treated with 0.2 to 5% by mass of a surface treatment agent, more preferably 0.2 to 3% by mass of a surface treatment agent, and still more preferably 0.3 to 2% by mass of a surface treatment agent.

The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the nonmagnetic inorganic filler. From the viewpoint of improving the dispersibility of the nonmagnetic inorganic filler, the amount of carbon per unit surface area of the nonmagnetic inorganic filler is preferably 0.02mg/m²Above, preferably 0.1mg/m²The above, more preferably 0.2mg/m²The above. On the other hand, from the viewpoint of suppressing an increase in the melt viscosity of the magnetic paste and the melt viscosity in the form of a sheet, it is preferably 1mg/m²The concentration is preferably 0.8mg/m or less²More preferably 0.5mg/m or less²The following.

(D) The amount of carbon per unit surface area of the non-magnetic inorganic filler material can be measured after the surface-treated non-magnetic inorganic filler material is subjected to a cleaning treatment with a solvent such as Methyl Ethyl Ketone (MEK). Specifically, a sufficient amount of MEK was added as a solvent to the nonmagnetic inorganic filler surface-treated with the surface treatment agent, and ultrasonic cleaning was performed at 25 ℃ for 5 minutes. After removing the supernatant liquid and drying the solid components, the amount of carbon per unit surface area of the non-magnetic inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by horiba, Ltd., can be used.

From the viewpoint of further improving the effect of the present invention, the specific surface area of the (D) nonmagnetic inorganic filler is preferably 1m²More than g, preferably 2m²More than g, particularly preferably 3m²More than g. The upper limit is not particularly limited, but is preferably 50m²A ratio of the total amount of the components to the total amount of the components is less than or equal to g, preferably 20m²10m below/g²Less than or equal to 5 m/g²The ratio of the carbon atoms to the carbon atoms is less than g. The specific surface area of the nonmagnetic inorganic filler can be obtained by adsorbing nitrogen gas onto the surface of a sample by the BET method using a specific surface area measuring apparatus (Macsorb HM-1210, manufactured by Mountech) and calculating the specific surface area by the BET multipoint method.

The content of the (D) nonmagnetic inorganic filler is preferably 10% by mass or less, more preferably 5% by mass or less, further more preferably 2% by mass or less, particularly preferably 1% by mass or less, with respect to 100% by mass of nonvolatile components in the resin composition. When the resin composition contains the nonmagnetic inorganic filler (D), the lower limit of the content is not particularly limited, and may be, for example, 0.001 mass% or more, 0.01 mass% or more, 0.1 mass% or more, 0.2 mass% or more, and the like.

< (E) other additives

The resin composition of the present invention may further contain (E) other additives as required. Examples of the other additives include other resin components, dispersants, curing retarders such as triethyl borate, flame retardants, thickeners, defoaming agents, leveling agents, adhesion imparting agents, resin additives such as coloring agents, and organic solvents. The content of other additives can be appropriately set by those skilled in the art.

< Property of resin composition >

Since the resin composition of the present invention uses a magnetic powder containing nickel as the magnetic powder, by using the magnetic cured product of the resin composition for the production of a circuit board, the amount of magnetic foreign matter that can be generated in the processing liquid in the wet plating process for the production of a substrate can be suppressed even when the surface of the magnetic cured product layer is not treated with an oxidizing agent.

The resin composition of the present invention is thermally cured to obtain a magnetic cured product, and the magnetic cured product is subjected to soft etching (Na) at 30 ℃₂S₂O₈100g/L，H₂SO₄(75% aqueous solution)), and the amount of mass decrease per unit surface area, i.e., the etching rate, after immersion for 1 minute is preferably 25mg/cm²Hereinafter, more preferably 20mg/cm²More preferably 15mg/cm or less²The concentration is preferably 12mg/cm²The following. The lower limit is not particularly limited, and may be set to 0.01mg/cm²Above, 0.1mg/cm²Above, 1mg/cm²And so on.

The magnetic cured product obtained by heat curing the resin composition of the present invention has a relative permeability (μ') at a measurement frequency of 100MHz and at room temperature of 23 ℃ of preferably 2 or more, more preferably 3 or more, still more preferably 3.5 or more, and particularly preferably 4 or more.

In one embodiment, the resin composition of the present invention contains the component (a), and thus a magnetic cured product having hardness suitable for polishing can be easily obtained. Therefore, in this embodiment, since the magnetic cured product of the resin composition of the present invention has excellent polishing properties, the polishing in the (2) polishing step of the wet plating process can be easily performed. The resin composition of the present invention contains the component (A), and thus the pencil hardness measured according to JIS K5600-5-4 on the surface of a magnetic cured product obtained by thermally curing the resin composition is preferably 5H or less, particularly preferably 4H or less. The lower limit is preferably not less than F, more preferably not less than H, still more preferably not less than 2H, particularly preferably not less than 3H.

< method for producing resin composition >

The resin composition can be produced, for example, by a method in which the blend components are stirred by a stirring device such as a three-roll mill, a rotary mixer, or a high-speed rotary mixer. The resin composition can be defoamed after production thereof or the like. Examples thereof include defoaming by standing, defoaming by centrifugal separation, vacuum defoaming, agitation defoaming, and defoaming by a combination thereof.

In the case of forming a magnetic cured product of a substrate, the resin composition may be used in the form of a paste resin composition (magnetic paste), or may be used in the form of a magnetic sheet including a layer of the resin composition.

Examples

The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following description, "part" and "%" representing amounts refer to "part by mass" and "% by mass", respectively, unless otherwise explicitly indicated.

< example 1 >

An epoxy resin ("ZX-1059", a mixture of a bisphenol A epoxy resin and a bisphenol F epoxy resin, manufactured by Nippon iron chemical Co., Ltd.) was mixed in an amount of 8.3 parts by mass, a curing agent ("2 MZA-PW", an imidazole-based curing accelerator, 2, 4-diamino-6- [2 '-methylimidazolyl- (1') ] -ethyl-s-triazine, manufactured by Sichuan chemical Co., Ltd.) in an amount of 1 part by mass, fumed silica ("RY 200", manufactured by Nippon AEROSIL Co., Ltd.) in an amount of 0.2 part by mass, and magnetic powder ("MA-RCO-5", an Fe-Ni alloy, having a Ni content of 50%, a Fe content of 50%, an average particle diameter of 3 μm, manufactured by DOWA Electronics Co., Ltd.) in an amount of 62 parts by mass to prepare a paste-like resin composition.

< example 2 >

In example 1, 62 parts by mass of a magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle diameter 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 53 parts by mass. In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< example 3 >

In example 1, 62 parts by mass of a magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle diameter 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 70 parts by mass. In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< example 4 >

In example 1, 62 parts by mass of magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle size 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 62 parts by mass of magnetic powder ("80% Ni-4 Mo", Fe-Ni-Mo alloy, Ni content 80%: Fe content 16%, Mo content 4%, average particle size 3 μm, manufactured by Epson Atmix Co., Ltd.). In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< example 5 >

In example 1, 62 parts by mass of a magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle diameter 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 44 parts by mass. In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< example 6 >

In example 1, 62 parts by mass of a magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle diameter 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 36 parts by mass. In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< comparative example 1 >

In example 1, 62 parts by mass of a magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle size 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 53 parts by mass of a magnetic powder ("AW 2-08PF 3F", Fe-Si alloy, average particle size 3 μm, manufactured by Epson Atmix Co., Ltd.). In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< comparative example 2 >

In example 1, 62 parts by mass of magnetic powder ("MA-RCO-5", Fe-Ni alloy, Ni content 50%: Fe content 50%, average particle size 3 μm, manufactured by DOWA Electronics Co., Ltd.) was changed to 62 parts by mass of magnetic powder ("Fe-6.5 Si-4.5 Cr", Fe-Si-Cr alloy, average particle size 3 μm, manufactured by Epson Atmix Co., Ltd.). In the same manner as in example 1 except for the above, a paste-like resin composition was prepared.

< test example 1: evaluation of solubility of magnetic powder

10g of magnetic powder as a raw material of the paste resin composition was weighed, and the paste resin composition was immersed in 100mL of 2N sulfuric acid at 40 ℃ for 5 minutes. Then, the magnetic powder was recovered using a filter paper (No. 5B60 mm. phi., manufactured by Kikusha Ltd.), dried at 100 ℃ for 60 minutes, and then the weight of the magnetic powder was measured using a precision balance to calculate the weight retention rate (%).

< test example 2: evaluation of relative magnetic permeability

As a support, a polyethylene terephthalate (PET) film (PET 501010 manufactured by Lindelco, Inc.; thickness: 50 μm) treated with a silicon-based release agent was prepared. The paste resin compositions of examples and comparative examples were uniformly applied to the release surface of the PET film by a doctor blade so that the thickness of the dried paste layer became 100 μm, to obtain a resin sheet. The obtained resin sheet was heated at 180 ℃ for 90 minutes to thermally cure the paste layer, and the support was peeled off to obtain a sheet-like cured product.

The sheet-like cured product thus prepared was cut into test pieces having a width of 5mm and a length of 18mm, and the test pieces were used as evaluation samples. For the evaluation sample, the relative permeability (. mu.) was measured at 23 ℃ at room temperature using 3-turn coil method using Agilent Technologies, "HP 8362B", with the measurement frequency set at 100 MHz.

< test example 3: evaluation of etching Rate

The cured sheet of test example 2 produced using the paste resin compositions of examples and comparative examples was cut into a size of 5cmx5cm, dried at 130 ℃ for 15 minutes, and the mass immediately after the drying was measured. This was designated as sample a, and the mass of sample a was designated as "X1". Sample A was immersed in Cleaner securiganteh 902(クリーナー & セキュリガンド 902) manufactured by Amett Japan K.K. for 5 minutes at 60 ℃ and then washed with water, followed by soft etching (Na) at 30 ℃₂S₂O₈：100g/L，H₂SO₄(75% aq.)14.2ml/L) for 1 minute, to obtain roughened sample a. The grained sample A was washed with water and the mass immediately after drying at 130 ℃ for 15 minutes was measured. The mass of the grained sample a immediately after the drying was assumed to be "X2". The etching rate (mg/cm) of a cured product of the resin composition by the roughening treatment was determined by the following formula²)；

Etching Rate (mg/cm)²)＝{(X1-X2)/25}。

< test example 4: evaluation of Pencil hardness

The surface of the cured sheet in test example 2 prepared using the paste resin compositions of examples and comparative examples, which was not opposed to the PET film, was measured for hardness of the surface of the cured sheet according to the test method of JIS K5600-5-4. The hardness of the hardest pencil that did not cause scratches was defined as the pencil hardness.

< test example 5: evaluation of insoluble matter amount

As a printed board, a board was prepared in which both surfaces of a glass cloth substrate epoxy resin both-side copper-clad laminate (thickness of copper foil 18 μm, thickness of board 0.8mm, R1515A manufactured by Sonar electric corporation) were etched by 1 μm with a microetching agent (CZ 8100 manufactured by Megger corporation) to roughen the copper surface. The prepared resin composition was uniformly applied to the prepared printed circuit board by a doctor blade to form a paste layer having a thickness of about 120 μm. The paste layer was heated at 130 ℃ for 30 minutes, and further at 145 ℃ for 30 minutes, thereby being thermally cured to form a magnetic cured product. The surface of the resulting cured magnetic material was polished, washed with high-pressure water (3.0MPa, 15 seconds), and heated at 180 ℃ for 30 minutes to perform heat treatment. The substrate thus produced was cut into 5cm square, and the substrate was used as an evaluation substrate.

The evaluation substrate (5cm square) WAs immersed in a reducing solution (60 ml, manufactured by Anmet Japan K.K.; 60ml, manufactured by Andute Japan K.K.; 3ml, manufactured by Andute Japan K.K.) at 40 ℃ for 24 hours. The precipitated precipitate was separated as an insoluble matter by filtration using a filter paper (No. 5b60mm phi, manufactured by tung mountain corporation), vacuum-dried for 5 hours, and then the amount of insoluble matter (mg/L) was measured using a precision balance, and evaluated according to the following criteria;

o: the insoluble matter content is less than 300mg/L

X: the insoluble matter amount is 300mg/L or more.

The nonvolatile components and the contents thereof of the resin compositions of examples and comparative examples, and the measurement results and evaluations of the test examples are shown in table 1 below.

[ Table 1]

From the examples it can be seen that: when a magnetic powder containing nickel is used as the magnetic powder, the amount of insoluble matter can be significantly suppressed. On the other hand, in the comparative example in which the magnetic powder containing nickel was not used, a large amount of insoluble matter was precipitated. Furthermore, the following embodiments show: when a magnetic powder containing nickel is used as the magnetic powder, the pencil hardness is lower and the grindability is excellent than when it is not used.

Description of the symbols

10-core substrate

11 supporting substrate

12 first metal layer

13 second metal layer

14 through hole

20 coating

30a resin composition

30 magnetic cured product

40 conductive layer

41 pattern conductor layer

100 inductor component

200 inner layer substrate

200a first major surface

200b second major surface

220 through hole

220a through-hole inner wiring

240 external terminal

300 magnetic part

310 magnetic sheet material

320a resin composition layer

320 first magnetic cured layer

330 support

340 second magnetic cured layer

360 through hole

360a via in-line

400 coil-shaped conductive structure

420 first conductor layer

420a bonding pad

440 second conductor layer.

Claims

1. A method for manufacturing a circuit board, comprising the following steps in order:

(1) a step of obtaining a magnetic cured product by thermally curing the resin composition,

(2) Polishing at least a part of the surface of the cured magnetic material, and

(3) a step of forming a conductor layer by wet plating on at least a part of the polished surface of the cured magnetic material,

wherein the resin composition comprises:

(A) magnetic powder containing nickel,

(B) An epoxy resin, and

(C) and (3) a curing agent.

2. The method for manufacturing a circuit board according to claim 1, wherein the component (A) is a nickel-iron alloy-based metal powder.

3. The method for manufacturing a circuit board according to claim 1 or 2, wherein the nickel content in the component (A) is 30 to 90 mass%.

4. The method for manufacturing a circuit board according to any one of claims 1 to 3, wherein the content of the component (A) in the resin composition is 70 to 98% by mass, assuming that 100% by mass of nonvolatile components in the resin composition are present.

5. The method of manufacturing a circuit board according to any one of claims 1 to 4, wherein the weight retention of the component (A) after immersion in 2N sulfuric acid at 40 ℃ for 5 minutes is 90% or more.

6. The method for manufacturing a circuit board according to any one of claims 1 to 5, wherein the component (B) contains an epoxy resin which is liquid at 25 ℃.

7. The method for manufacturing a circuit board according to any one of claims 1 to 6, wherein the component (C) is a curing agent selected from an acid anhydride curing agent, an amine curing agent, and an imidazole curing agent.

8. The method for producing a circuit board according to any one of claims 1 to 7, wherein the pencil hardness of the surface of the magnetic cured product obtained in the step (1) measured according to JIS K5600-5-4 is F to 5H.

9. The method for producing a circuit board according to any one of claims 1 to 8, wherein the magnetic cured product obtained in the step (1) is subjected to a soft etching solution (Na) at 30 ℃₂S₂O₈100g/L，H₂SO₄(75% aqueous solution)) was immersed for 1 minute, and the etching rate was 25mg/cm²The following.

10. The method of manufacturing a circuit board according to any one of claims 1 to 9, wherein the resin composition is in the form of a paste.

11. A resin composition comprising:

(A) magnetic powder containing nickel,

(B) An epoxy resin, and

(C) and (3) a curing agent.